I have a zeovit reef tank and use HW-Marine Reefer salt mix without issues. Prior to setting up my zeovit system I used instant ocean and I always had a brown residue in my mixing container. For this alone I won't use IO anymore. I'm sure this was extra nutrients that is not need in a system the is ultra low nutrients to begin with. I would take a look at the HW-Marine mix or the KZ Reefer's Best salt mix. I have also found that the frequency and quantity of my water changes is less with Zeovit.